Hello, I am trying to plot 4 survival curve on one graph but this seem hard to do in R. What I am trying to do is to superimpose all 4 survival curves on one graph. I tried the following : datastat<-read.table("survival curve A2.txt", header= TRUE, sep="\t", quote="", comment.char="", na.strings="#N/A") # Plot attach(datastat) names(datastat) a<-survfit(Surv(Weeks, A==1), conf.type="none") a b<-survfit(Surv(Weeks, B==1), conf.type="none") b c<-survfit(Surv(Weeks, C==1), conf.type="none") c d<-survfit(Surv(Weeks, D==1), conf.type="none") d plot(a,b,c,d) But plot function doesn't work. The data is as follows : Weeks A B C D 1 0 0 0 0 2 0 0 0 0 3 0 0 0 0 4 0 0 0 0 5 0 0 0 0 6 0 0 0 0 7 0 0 0 0 8 0 0 0 0 9 0 0 0 0 10 0 0 0 0 11 0 0 0 0 12 1 0 0 0 13 0 0 0 1 14 0 0 0 1 15 0 0 0 1 16 0 0 1 2 17 0 0 1 1 18 0 0 1 2 19 0 1 1 1 20 0 0 2 1 21 0 0 1 2 22 0 0 1 1 23 0 0 0 2 24 0 0 1 2 25 0 0 1 1 26 0 0 1 1 27 0 0 2 1 28 0 0 0 1 29 0 0 1 2 30 0 0 1 1 31 0 0 1 0 32 0 0 1 1 33 0 0 1 0 34 0 0 1 0 35 0 0 1 0 36 0 0 0 0 37 0 0 1 0 38 0 0 0 0 39 0 1 1 0 40 0 0 1 0 41 0 0 1 0 42 0 0 0 0 43 0 0 1 0 Any help with this is appreciated. It seems easy to do but I played with par() and other things but couldn't get all 4 curves to plot on one graph. Many thanks rifat

Hi Rifat, I think this question might be more appropriate for R-help. I would recommend trying RSiteSearch() to look for possible solutions to your question. Conceptually, I suspect what you will need to do is: - plot one survfit result - use lines() or points() and the relevant data extracted from the other fits to add to the existing plot. HTH, + seth